Titanium dioxide nanotube arrays modified with a nanocomposite of silver nanoparticles and reduced graphene oxide for electrochemical sensing

We report on a new nanocomposite material for electrochemical sensing of hydrogen peroxide using a titanium dioxide nanotube arrays modified with reduced graphene oxide onto which silver nanoparticles (AgNPs) were chemically deposited. Transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and energy-dispersive X-ray and Raman spectroscopy were used to characterize its microstructure and morphology. The results demonstrated that the AgNPs were uniformly dispersed on the surface of the modified electrode which was investigated with respect to capability for sensing hydrogen peroxide (H2O2). Under optimized experimental condition, the electrode responds to H2O2 with a sensitivity of 1152 mu A mM(-1) cm(-2) at a working potential of -0.6 V. The current response is linearly related to the concentration of H2O2 in the range from 50 to 15.5 mM (with a correlation coefficient of 0.9997), and the detection limit is 2.2 mu M. The sensor exhibits good stability and excellent selectivity for H2O2. By immobilizing glucose oxidase on the surface of this electrode, a glucose biosensor was obtained that responds to glucose in the 0.5 to 50 mM concentration range.